Message-based exchange of access point pilot signature indicators

ABSTRACT

An access point is identified based on a plurality of pilot signatures. Here, in addition to transmitting a pilot signal that is encoded (e.g., spread/scrambled) using a particular pilot signature, an access point transmits a message that includes at least one indication of at least one other pilot signature. For example, an access point may use one PN offset to generate a pilot signal and transmit a message that identifies at least one other PN offset. An access terminal that receives the pilot signal and the message may then generate a pilot report that identifies all of these pilot signatures. Upon receiving a handover message including this pilot-related information, a target network entity with knowledge of the pilot signatures assigned to that access point may then accurately identify the access point as a target for handover of the access terminal.

CLAIM OF PRIORITY

This application is a continuation application of U.S. Non-Provisionalapplication Ser. No. 12/849,924, filed Aug. 4, 2010, and assignedAttorney Docket No. 093165U1, which claims the benefit of and priorityto commonly owned U.S. Provisional Patent Application No. 61/231,635,filed Aug. 5, 2009, and assigned Attorney Docket No. 093165P1. Thisapplication incorporates by reference each of these applications intheir entireties.

CROSS-REFERENCE TO RELATED APPLICATION

This application is related to commonly owned U.S. patent applicationSer. No. 12/849,947, entitled “ACCESS POINT IDENTIFICATION BASED ONMULTIPLE PILOT SIGNATURE INDICATORS,” and assigned Attorney Docket No.093165U2, the disclosure of which is hereby incorporated by referenceherein.

BACKGROUND

1. Field

This application relates generally to communication and morespecifically, but not exclusively, to the use of multiple pilotsignature indicators for identifying an access point.

2. Introduction

A wireless communication network may be deployed over a geographicalarea to provide various types of services (e.g., voice, data, multimediaservices, etc.) to users within that geographical area. In a typicalimplementation, access points (e.g., macro access points providing macrocell coverage) are distributed throughout a network to provide wirelessconnectivity for access terminals (e.g., cell phones) that are operatingwithin the geographical area served by the network.

As the demand for high-rate and multimedia data services rapidly grows,there lies a challenge to implement efficient and robust communicationsystems with enhanced performance. To supplement conventional networkaccess points (e.g., macro access points), small-coverage access pointsmay be deployed (e.g., installed in a user's home) to provide morerobust indoor wireless coverage or other coverage for access terminals.Such small-coverage access points may be referred to as, for example,femto access points, femto cells, home NodeBs, home eNodeBs, or accesspoint base stations. Typically, such small-coverage access points areconnected to the Internet and the mobile operator's network via a DSLrouter or a cable modem.

As the access terminal roams throughout the geographical area associatedwith the network, the access terminal may move away from its servingaccess point and move closer to another access point. Consequently, whenan access terminal gets close to a particular access point, it may bedesired to handover (i.e., idle or active handover) the access terminalto that particular access point if that access point provides betterradio frequency (RF) coverage and/or additional services.

To enable such handover, access terminals in a network regularly monitorfor pilot signals from nearby access points to identify potential targetaccess points. To facilitate this monitoring, each access pointtransmits a pilot signal with a unique pseudo-random noise (PN)spreading code. Different access points in the network may use a knownpilot spreading code (also sometimes known as scrambling code) withdifferent phase offsets—commonly referred to as PN offsets (e.g., forthe case of a cdma2000 network). Thus, an access point may be identifiedbased on the PN offset used by that access point. In conventional macronetworks, a target access point for handover of an access terminalbetween two cells is identified based on a forward link (FL) pilotreport sent by the access terminal. Such a report may be referred to as,for example, a pilot strength measurement message (PSMM) or as a RouteUpdate (in CDMA high rate packet data technology). The pilot reportincludes an indication of the FL signal quality (typically pilotstrength Ecp/Io) of neighboring access points and pilot phase associatedwith each of these access points. The pilot phase that is reported maythen be mapped to the signature (e.g. pilot PN offset) used by aparticular access point. In this way, the identity of the access pointthat transmitted given pilot signal may be determined assuming no otheraccess points are using the signature.

For effective active (i.e., connected) handover of an access terminalfrom one access point to another, the network needs to be able touniquely identify the target access point. However, the number ofavailable PN offsets is typically limited. In some cases, the number ofavailable PN offsets may be limited by the size of the neighbor listthat is used to assist access terminals in searching for neighboring PNsignals. Here, to reduce overhead and improve efficiency, it may bedesirable to limit the number of entries in the neighbor list advertisedby a macro access point to a relatively small number (e.g., 20-40).

Consequently, in the event a relatively large number of small-coverageaccess points are deployed in the same area (e.g., within the coverageof a single macro cell), several of these access points may use the samePN offset for their pilot signals. Unique identification for activehandover to such an access point may therefore be difficult due to PNoffset confusion. Specifically, confusion may exist as to which accesspoint (e.g., which potential handover target) is being identified whenan access terminal in the network reports to its serving access point(e.g., the handover source) that a pilot signal having a given PN offsethas been received.

Conventional solutions for dealing with the above problem include amobile sensing scheme and a scheme where an access point advertises acell identifier. For example, in a mobile sensing scheme, candidatetarget femto cells are requested to detect signals from an accessterminal on the reverse link (RL) and report this information to thenetwork. The network then identifies the target based on which femtocell reported the best FL signal. In practice, however, such a schememay have scalability problems in the event a large number of femto cellsare deployed. In addition, such a scheme may not provide a sufficientlevel of accuracy due to FL/RL imbalances (e.g., the femto cell thatreports the strongest FL signal may not be the intended target).

In a cell identifier advertising scheme, a femto cell may advertise anaccess point identification message that includes a mobile switchingcenter (MSC) related identifier (IOS_MSC_ID) and a cell relatedidentifier (IOS_CELL_ID) that uniquely identifies that femto cell at thenetwork. An access terminal may then report this information to thenetwork via a handoff supplementary information notification message.However, such a scheme requires that the macro access points be upgradedto support the handoff supplementary information notification message.In addition such a scheme does not support legacy access terminals. Inview of the above, there is a need for effective techniques foridentifying access points so that other nodes in the network mayefficiently communicate with the access points.

SUMMARY

A summary of sample aspects of the disclosure follows. In the discussionherein, any reference to the term aspects may refer to one or moreaspects of the disclosure.

The disclosure relates in some aspects to using a plurality of pilotsignatures to provide a unique signature for identifying an accesspoint. For example, an access point may transmit a pilot signal that isencoded (e.g., spread/scrambled) based on a particular pilot signature,and also advertise at least one other pilot signature (e.g., bytransmitting a message that includes at least one indication of at leastone other pilot signature). As a specific example, an access point mayuse one PN offset to generate a pilot signal and transmit a message thatidentifies at least one other PN offset. An access terminal thatreceives the pilot signal and the message may then generate a pilotmeasurement report that identifies all of these pilot signatures.Consequently, the pilot measurement report may take the form of a legacypilot measurement report that may handled by a legacy network, whileproviding pilot-related information (e.g., a defined set of PN offsets)that more accurately identifies the access point. Upon receiving ahandover message including this pilot-related information, a targetnetwork entity with knowledge of the pilot signatures assigned to thataccess point may then accurately identify the access point as a targetfor handover of the access terminal, as warranted.

The disclosure relates in some aspects to configuring an access pointand one or more network entities with the pilot signature-relatedinformation that identifies an access point. For example, a networkentity may allocate a plurality of pilot signature indicators (e.g., PNoffsets) for an access point. The network entity may then send a messageincluding the allocated pilot signature indicators to the access point.The network entity also may send a message including the allocated pilotsignature indicators to one or more other network entities (e.g.,entities that may need to identify the access point based on the pilotsignature indicators).

The disclosure relates in some aspects to an access point thatadvertises a plurality of pilot signatures. For example, upon receivingan allocation of pilot signature indicators, the access point maytransmit a pilot signal based on one of these pilot signatureindicators. In addition, the access point may generate and then transmita message including the other allocated pilot signature indicator(s).

The disclosure relates in some aspects to an access terminal thatgenerates a pilot report that includes indications of all of the pilotsignatures allocated for an access point. For example, upon receivingthe pilot signal and message transmitted by an access point, the accessterminal may generate and then transmit a pilot report that includes atleast one indication that is based on the received pilot signatureindicator(s) and one indication based on the pilot signature associatedwith the received pilot signal.

The disclosure relates in some aspects to a identifying an access pointas a handover target based on received information that is indicative ofall of the pilot signatures allocated for that access point. Forexample, a network entity may determine (e.g., obtain) a mapping thatmaps different access points to different sets of cell identifiers orpilot signature indicators. Thus, upon receiving a handover-relatedmessage for an access terminal that includes a plurality of cellidentifiers or pilot signature indicators, the network entity mayidentify one of these access points as the handover target based on themapping and the received cell identifiers or pilot signature indicators.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other sample aspects of the disclosure will be described inthe detailed description and the appended claims that follow, and in theaccompanying drawings, wherein:

FIG. 1 is a simplified block diagram of several sample aspects of acommunication system adapted to identify an access point based on aplurality of pilot signature indicators;

FIGS. 2 and 3 are a flowchart of several sample aspects of operationsthat may be performed in conjunction with identifying an access pointbased on a plurality of pilot signature indicators;

FIG. 4 is a simplified block diagram of several sample aspects of acommunication system adapted to identify an access point based on aplurality of cell identifiers associated with pilot signature indicatorsallocated to the access point;

FIG. 5 is a simplified block diagram of several sample aspects of acommunication system adapted to identify an access point based on aplurality of PN phases associated with pilot signature indicatorsallocated to the access point;

FIG. 6 is a flowchart of several sample aspects of operations that maybe performed in conjunction with configuring pilot signature indicatorsfor an access point;

FIG. 7 is a flowchart of several sample aspects of operations that maybe performed in conjunction with advertising pilot signature indicatorsat an access point;

FIG. 8 is a flowchart of several sample aspects of operations that maybe performed in conjunction with providing a pilot report based on pilotsignature indicators received from an access point;

FIG. 9 is a flowchart of several sample aspects of operations that maybe performed in conjunction with identifying a target access point basedon pilot signature indicator-based information;

FIG. 10 is a simplified block diagram of several sample aspects of aCDMA 1x communication system adapted to identify an access point basedon a plurality of pilot signature indicators;

FIG. 11 is a simplified block diagram of several sample aspects of aCDMA HRPD communication system adapted to identify an access point basedon a plurality of pilot signature indicators;

FIG. 12 is a simplified block diagram of several sample aspects ofcomponents that may be employed in communication nodes;

FIG. 13 is a simplified diagram of a wireless communication system;

FIG. 14 is a simplified diagram of a wireless communication systemincluding femto nodes;

FIG. 15 is a simplified diagram illustrating coverage areas for wirelesscommunication;

FIG. 16 is a simplified block diagram of several sample aspects ofcommunication components; and

FIGS. 17-21 are simplified block diagrams of several sample aspects ofapparatuses configured to perform operations related to identifying anaccess point based on a plurality of pilot signature indicators astaught herein.

In accordance with common practice the various features illustrated inthe drawings may not be drawn to scale. Accordingly, the dimensions ofthe various features may be arbitrarily expanded or reduced for clarity.In addition, some of the drawings may be simplified for clarity. Thus,the drawings may not depict all of the components of a given apparatus(e.g., device) or method. Finally, like reference numerals may be usedto denote like features throughout the specification and figures.

DETAILED DESCRIPTION

Various aspects of the disclosure are described below. It should beapparent that the teachings herein may be embodied in a wide variety offorms and that any specific structure, function, or both being disclosedherein is merely representative. Based on the teachings herein oneskilled in the art should appreciate that an aspect disclosed herein maybe implemented independently of any other aspects and that two or moreof these aspects may be combined in various ways. For example, anapparatus may be implemented or a method may be practiced using anynumber of the aspects set forth herein. In addition, such an apparatusmay be implemented or such a method may be practiced using otherstructure, functionality, or structure and functionality in addition toor other than one or more of the aspects set forth herein. Furthermore,an aspect may comprise at least one element of a claim.

FIG. 1 illustrates several nodes of a sample communication system 100(e.g., a portion of a communication network). For illustration purposes,various aspects of the disclosure will be described in the context ofone or more access terminals, access points, and network entities thatcommunicate with one another. It should be appreciated, however, thatthe teachings herein may be applicable to other types of apparatuses orother similar apparatuses that are referenced using other terminology.For example, in various implementations access points may be referred toor implemented as base stations, access networks, or NodeBs, and so on,while access terminals may be referred to or implemented as userequipment, or mobile stations, and so on.

Access points in the system 100 provide one or more services (e.g.,network connectivity) for one or more wireless terminals (e.g., accessterminal 102) that may be installed within or that may roam throughout acoverage area of the system 100. For example, at various points in timethe access terminal 102 may connect to an access point 104, an accesspoint 106, or some other access point in the system 100 (not shown).Each of these access points may communicate with one or more networkentities (represented, for convenience, by network entities 108) tofacilitate wide area network connectivity. A network entity may takevarious forms such as, for example, one or more radio and/or corenetwork entities. Thus, in various implementations a network entity mayrepresent functionality such as at least one of: radio network control,network management (e.g., via an operation, administration, management,and provisioning entity), call control, session management, mobilitymanagement, gateway functions, interworking functions, or some othersuitable network functionality.

In accordance with the teachings herein, a pilot signature configurationentity 110 allocates a plurality of pilot signature indicators forcertain access points in the system 100. For example, the pilotsignature configuration entity 110 may allocate two or more PN offsetsfor the access point 104 (e.g., a femto cell). The pilot signatureconfiguration entity 110 also may send this information to otherentities in the system 100. For example, a target identification entity112 may use this pilot signature information to identify the accesspoint as a target for a handover procedure.

The access point 104 uses one of its allocated pilot signatureindicators for transmitting a pilot signal and advertises the otherallocated pilot signature indicator(s). That is, the access point 104may broadcast a message that identifies the other allocated pilotsignature indicator(s). This message also may include a defined (e.g.,artificial) indication of pilot strength (e.g. Ecp/Io—the ratio ofreceived pilot energy to the total received power) associated with eachpilot signature indicator included in the message.

When the access terminal 102 is in the vicinity of the access point 104,the access terminal 102 may receive the pilot signal and the messagetransmitted by the access point 104. In accordance with the teachingsherein, the access terminal 102 generates a pilot report that includespilot signature indicators based on the received pilot signal and thereceived message. For example, the pilot report may include anindication of the PN offset that the access point 104 used to transmitthe pilot signal and the pilot report may include one or moreindications of the PN offsets that were identified in the message sentby the access point 104. For each PN offset, this report may includepilot measurement information such as, for example, the PN phasecorresponding to the PN offset, as well as a corresponding indication ofpilot strength. Also, in the event there are other access points in thevicinity of the access terminal, the pilot report may include similarpilot signature-related information for these other access points.

In accordance with conventional practice, at some point in time, theaccess terminal 102 sends the pilot report to its current serving accesspoint (e.g., access point 106). If the information in the pilot reportindicates that handover of the access terminal is warranted, a handovermessage including information based on the pilot report may be sent toanother network entity (e.g., the entity 112) that is able to determinethe identity of the target access point for handover of the accessterminal 102. In accordance with conventional practice, this handovermessage may include, for example, the reported PN phases or cellidentifiers corresponding to the reported PN phases. The entity 112 maythen use the pilot signature configuration information it received fromthe entity 110 to identify any access points that use PN phases thatmatch those indicated by the pilot signature-related informationreceived via the handover message.

These and other aspects of the disclosure will now be described in moredetail in conjunction with the flowchart of FIGS. 2 and 3. Forconvenience, the operations of FIGS. 2 and 3 (or any other operationsdiscussed or taught herein) may be described as being performed byspecific components (e.g., components as shown in FIGS. 1, 10, 11, and12). It should be appreciated, however, that these operations may beperformed by other types of components and may be performed using adifferent number of components. It also should be appreciated that oneor more of the operations described herein may not be employed in agiven implementation.

As represented by block 202 of FIG. 2, at some point in time a networkentity allocates pilot signature indicators for an access point. Forexample, a femto management server may allocate two or more PN offsetsfor a femto cell when that femto cell is deployed. In such a case, thepilot signature indicators may identify the PN offsets (e.g., a numberfrom 0 to 511 for a case where 512 PN offsets are available for use) ormay identify the corresponding PN phases (e.g., the number of chipscorresponding to the phase shift from PN phase 0). It should beappreciated that other types of pilot signature indicators may beemployed in different implementations. For example, a pilot signatureindicator may identify a primary scrambling code (PSC) or a physicalcell identifier (PCI) that is used for spreading (scrambling) a pilotsignal.

The network entity allocates one of the pilot signature indicators fortransmitting a pilot signal and the remaining pilot signatureindicator(s) is/are used for identification of the access point. Forexample, in a case where three pilot signature indicators are allocatedfor an access point, the access point generates a pilot signal based onone of the pilot signature indicators and advertises the other two pilotsignature indicators. As discussed in more detail below, a pilotsignature indicator allocated for non-pilot signal use may be obtainedfrom a set of pilot signature indicators that are not allocated forpilot signal use in a corresponding area of the network (e.g., thecoverage area managed by a particular mobile switching center).

In some cases, the network entity also defines a pilot signal strengthindication to be advertised along with each advertised pilot signatureindicator. As discussed in more detail below, this defined pilot signalstrength indication may subsequently be used by an access terminal togenerate a pilot report.

As represented by block 204, the network entity configures the accesspoint by sending a message including the allocated pilot signatureindicators to the access point. If applicable, this message alsoincludes one or more pilot signal strength indications. As discussedherein, the network entity may also send this configuration informationto one or more other entities in the network.

The access point receives the pilot signature indicators as representedby block 206. Then, based on one of the received pilot signatureindicators, the access point transmits a pilot signal as represented byblock 208. For example, the access point may transmit its pilot signalthrough the use of a spreading code (e.g., a PN spreading code) that isbased on the allocated pilot indicator (e.g., a particular PN offset).

As represented by block 210, the access point also generates andtransmits a message (e.g., an access point identifier message (APIDM))that includes at least one of the received pilot signature indicatorsother than the received pilot signal that is used to transmit the pilotsignal. For example, the access point may receive indications of PNoffsets 0 and 2 at block 206. The access point may then use PN offset 0for sending the pilot signal at block 208. In this case, the messagegenerated at block 210 will include an indication that is based on PNoffset 2. In some implementations, the message also may optionallyinclude an indication that is based on PN offset 0 in this example.

The message generated at block 210 may include a pilot signal strengthindication for each advertised pilot signature indicator. As mentionedabove, in some cases the access point is configured with the pilotsignal strength indication(s). In other cases, however, the access pointmay define the pilot signal strength indication(s).

As represented by blocks 212 and 214, an access terminal in the vicinityof the access point may receive the pilot signal and the messagetransmitted by the access point (as well as similar informationtransmitted by any other nearby access points). Accordingly, the accessterminal may acquire the pilot signature-related information transmittedby the access point. For example, by decoding the received pilot signal,the access terminal may identify the PN offset used to transmit thepilot signal. In addition, the access terminal may read the PN offsetsincluded in the received message.

The information received at blocks 212 and 214 may trigger the sendingof a pilot report. For example, sending of a report may be triggered ifa received signal strength of a pilot signal exceeds a certain thresholdlevel (e.g., exceeds the received signal strength of a signal from theserving macro cell by a defined margin).

As represented by block 216 of FIG. 3, the access terminal generates andtransmits a pilot report that includes at least one indication based onthe pilot signature indicator(s) received via the message. Such anindication may take various forms depending on the form of the receivedpilot signature indicator and whether the access terminal converts thereceived indicator to another form. For example, in some cases theaccess terminal receives PN offsets from the access point and convertsthese PN offsets to the corresponding PN phases, and includesindications of these PN phases in the pilot report. In other cases, theaccess terminal receives PN phases from the access point and includesindications of these PN phases in the pilot report.

The pilot report also includes a pilot signal strength indication foreach indication entry in the report. For example, the access terminalmay measure the signal strength of the pilot signal received at block212 and include an indication of this value in the pilot report. Inaddition, the access terminal may include the pilot signal strengthindications received via the message at block 214 in the pilot report.

Advantageously, this pilot report may be provided in a form that iscompatible with the operation of legacy network entities. For example,for hard handover for legacy mobile stations (and also in CDMA HRPD),only pilot measurements (e.g., PN phases and strengths) are reported. Asdiscussed herein, the pilot report transmitted at block 216 may simplyinclude PN phase and received signal strength information. Thus, thepilot report may be handled by legacy entities even though the pilotreport includes additional information (e.g., additional PN phaseindications) that is ultimately used in combination by another networkentity to uniquely identify the access point.

As represented by block 218, a network entity (e.g., a macro accesspoint) currently serving the access terminal receives the pilot report.In accordance with conventional practice, this network entity or anassociated network entity (e.g., a mobile switching center) maydetermine whether handover of the access terminal is warranted. Forexample, handover operations may be triggered if one of the receivedsignal strength values in the pilot report exceeds a similar macrosignal level by a defined margin.

In some implementations (e.g., CDMA 1x technology), the source networkentity converts the received pilot signature indicators to another formof indication. For example, a macro base station (or an associatedmobile switching center) may convert each received PN phase to acorresponding cell identifier based on a mapping known to that networkentity. In such a case, the source operations describe here may beperformed on the basis of the corresponding cell identifiers.

The source network entity (e.g., a mobile switching center) also maydetermine whether it can identify the handover target. For example, ifthe highest received signal strength is associated with a PN phase (or acell identifier as discussed above) that the network entity knows isbeing used by a particular access point, the network entity maycommunicate with that access point to facilitate handover of the accessterminal. On the other hand, if the network entity does not know theidentity of the access point associated with that PN phase (or cellidentifier), the network entity may identify another network entity(e.g., through the use of a look-up table) that advertises that it doesknow the identity of the access point. For example, configurationinformation in a source macro mobile switching center may indicate thatanother mobile switching center can handle a particular cell identifier,and that yet another mobile switching center can handle another cellidentifier. In such a case, the source network entity may send ahandover message including the received or generated handover-relatedinformation to the other network entity as represented by block 220.

From the above it may be seen that a legacy macro access point may needto be configured with the PN phase indicators that are allocated forbeing advertised (e.g., via an APIDM). However, a mechanism forconfiguring an access point in this manner is already available inlegacy systems Implementation of the teachings herein may thus onlyinvolve configuring the legacy macro access points with the PN phase(and, in some cases, associated cell identifier) information using thismechanism. Advantageously, the legacy entity does not need to know aboutthe actual combinations allocated for an access point. Instead, thisinformation is provided to another entity (e.g., a femto convergenceserver or a femto gateway) that performs the actual operation ofidentifying the access point.

As represented by block 222, a target network entity (e.g., a femtoconvergence server or a femto gateway) may receive the handover messagesent by the source network entity at block 220. Thus, this message mayinclude, for example, the pilot signature indicators (e.g., PN phaseindicators) or the cell identifiers discussed above. In addition, thehandover message may include the received pilot signal strengthindications described above.

As represented by block 224, at some point in time, the target networkentity determines a pilot-related information mapping for a set ofaccess points (e.g., the access points under the supervision of thenetwork entity). This mapping may take different forms in differentimplementations. For example, in some cases, a given entry of themapping maps a given access point with the set of the pilot signatureindicators (e.g., PN phase indicators or PN offset indicators) allocatedfor that access point. In some cases, a mapping entry maps a givenaccess point with a set of cell identifiers that are, in turn, assignedto the set of the pilot signature indicators that are allocated for theaccess point.

As represented by block 226, the target network entity may thereforeidentify the target access point for handover of the access terminalbased on the mapping and the received pilot signature-relatedinformation. For example, the network entity may compare the received PNphases indicators (or cell identifiers) with the entries in the mappingto identify the access point that transmitted the pilot signal and themessage that caused these PN phases indicators (or cell identifiers) tobe sent to the target network entity. As a specific example, if thehighest received signal strength in the measurement report is associatedwith PN phases 0 and 2, the network entity determines which entry in themapping contains this set of PN phases. The network entity may then lookup the identity of the corresponding access point from this entry.

As represented by block 228, once the appropriate target has beenidentified, handover of the access terminal to the target is performed.For example, the target network entity may facilitate communicationbetween the source access point and the target access point to completethe handover.

FIG. 4 illustrates a simplified example of a CDMA 1x system 400 thatdescribes sample message flow that may be used in such a system inaccordance with the teachings herein. Here, a femto management system(FMS) maintains a pool of PN offsets (PN1-PN15) that may be allocated tofemto cells. In this example, PN2-PN4 are allocated for a particularfemto cell as represented by the arrow 402. The FMS also provisions thisinformation to an appropriate network entity (e.g., a femto convergenceserver (FCS) or femto MSC) as represented by the arrow 404. The femtocell broadcasts a message (e.g., APIDM) that includes PN2-PN4 and thismessage is received by a mobile station (MS) in the vicinity. The MSthen transmits a pilot strength measurement message (PSMM) that includesthe corresponding PN phase information (PN phase2-PN phase4) to itsserving macro base station (BS). The macro BS, in turn, sendscorresponding cell identifiers (cell ID2-cell ID4) to its macro MSC (viaan A1p interface) which forwards the cell identifiers to the targetFCS/MSC (via an IS-41 interface). Here, there is a 1:1 mapping betweeneach PN offset (and PN phase) and each cell ID. The target FCS/MSC thendetermines the handover target based on the reported cell IDs.

FIG. 5 illustrates a simplified example of a CDMA HRPD system 500 thatdescribes sample message flow that may be used in such a system inaccordance with the teachings herein. Again, a femto management system(FMS) maintains a pool of PN offsets (PN1-PN15) that may be allocated tofemto cells. PN2-PN4 are allocated for a particular femto cell asrepresented by the arrow 502. The FMS also provisions this informationto an appropriate network entity (e.g., a femto gateway (FGW)) asrepresented by the arrow 504. The femto cell then broadcasts a message(e.g., APIDM) that includes PN2-PN4 that may be received by an accessterminal (AT) in the vicinity. The AT transmits a Route Update messagethat includes the corresponding PN phase information (PN phase2-PNphase4) to its serving macro access network (AN). The macro AN, in turn,sends the PN phase information to the target FGW (by embedding the RouteUpdate message in an A16 session transfer request). The target FGW thendetermines the handover target based on the reported PN phases.

With the above in mind, additional details of operations that may beperformed in accordance with the teachings herein will be described withreference to FIGS. 6-9.

FIG. 6 describes sample operations that may be performed to allocatepilot signature indications for an access point. These operations may beperformed, for example, by a network entity such as a femto managementsystem.

As represented by block 602, a set of unallocated pilot signatures thatmay be allocated to access points (e.g., femto cells) are identified.For example, this set may comprise all of the PN offsets that not beingused by macro access points in a given area.

In some cases, this set of pilot signatures may be designated fornon-pilot transmission use only. For example, out of a set of availablepilot signatures (e.g., 256 available PN offsets), a first group may bedesignated for use for transmitting pilot signals, while a second groupmay be designated only for being sent in a message (e.g., APIDM) by anaccess point. In other words, pilot signatures of the second group maynot be used for scrambling transmitted pilot signals. Advantageously,this second group of pilot signatures may be used to identify accesspoints without the need to advertise these pilot signatures in a macroneighbor list, and without the need for access terminals to conductsearches for these pilot signatures. In some cases, a pilot signaturethat is designated for transmitting pilot signals also may be designatedfor being advertised (e.g., in an APIDM).

The allocation of a set of pilot signatures may be made for a designatedarea. For example, the designation of a set of pilot signatures so thatthey will only be advertised in APIDMs may only apply to an areacorresponding to the coverage areas of access points supervised orcontrolled by a given femto management system or a given mobileswitching center. Thus, in some aspects, a pilot signature indicator maycomprise a value that is indicative of a pilot signature that is notcurrently allocated for pilot scrambling use by any access pointsassociated with an area of a wireless network.

As represented by block 604, at some point in time, pilot signatureallocation for an access point is commenced. For example, a femtomanagement system may initiate this allocation when a femto cell isdeployed, powered-up, reset, or reconfigured.

As discussed herein, this process may involve allocating multiple pilotsignature indicators for a single access point to provide a uniquesignature for that access point that may then be used to uniquelyidentify the access point during handover. Accordingly, as representedby block 606, a determination may thus be made that more than one pilotsignature indication is to be allocated for a given access point (e.g.,for access point of a given type). For example, all femto cells in agiven network may be allocated more than one PN offset while all otheraccess points in that network may be allocated a single PN offset.

Thus, as represented by block 608, the allocation entity may allocate aplurality of pilot signature indicators (e.g., each of which comprises aspecific value corresponding to a particular PN offset or PN phase) fora given access point. As discussed above, one of these pilot signatureindicators is allocated for transmission of a pilot signal by the accesspoint, while the remaining pilot signature indicator(s) is/are allocatedfor being advertised by the access point (e.g., via an APIDM).

As represented by block 610, the allocation entity may optionally definepilot signal strength information for each pilot signature indicatorthat is allocated for being advertised. In some cases, this pilot signalstrength is set to a value that ensures there will not be undueinterference with network handover trigger mechanisms (e.g., theselected value won't trigger unnecessary initiations of handoverprocedures). For example, the pilot signal strength may be defined at avalue that is below a minimum received signal strength that is specifiedfor maintaining a call with a macro access point.

In some implementations, the defined pilot signal strength may be usedto define the identity signature for the access point. That is, anidentity signature for a given access point may be generated byallocating different PN offset indictors (or PN phase indicators) anddifferent associated pilot strength values. Thus, as discussed below, anetwork entity (e.g., femto convergence server or femto gateway) alsomay take these pilot signal strength indications into account whenidentifying the target for a handover.

As represented by block 612, the allocation entity sends a message thatincludes the allocated pilot signature indicators to the access point.As discussed herein, this message may include PN offset indicators, PNphase indicators, PSC indicators, PCI indicators, or some other type ofindicators. In addition, this message may include the pilot signalstrength indication(s) defined at block 610.

As represented by block 614, the allocation entity also sends a messagethat includes the allocated pilot signature indicators (and, optionally,defined pilot signal strength indication(s)) to one or more othernetwork entities. For example, this message may be sent to a femtoconvergence server, a femto gateway (also referred to as a femto cellgateway), an access network, some other entity, or some combination ofthese entities.

FIG. 7 describes sample operations that may be performed by an accesspoint in conjunction with advertising its pilot signature-relatedinformation. These operations commence at block 702 where the accesspoint receives a configuration message that includes the pilot signatureindicators allocated for that access point. In addition, as discussedabove, in some cases this message includes defined pilot signal strengthinformation for one or more of the pilot signature indicators.

As represented by block 704, the access point may optionally definepilot signal strength information for each pilot signature indicatorthat is allocated for being advertised (e.g., in the event the accesspoint did not receive any pilot signal strength indications from thefemto management system). In some cases, a pilot signal strengthindication is set to a value that ensures there will not be undueinterference with network handover trigger mechanisms (e.g., asdiscussed above).

As represented by block 706, the access point transmits a pilot signalbased on one of the allocated pilot signature indicators. For example,the access point may use an allocated PN offset to adjust the phase ofthe spreading code the access point uses to transmit the pilot signal.

As represented by block 708, the access point generates a message thatincludes at least one of the received pilot signature indicators otherthan the received pilot signal that is used to transmit the pilotsignal. This message also may include a pilot signal strength indicationfor each advertised pilot signature indicator as discussed herein.

As represented by block 710, the access point transmits the messagegenerated at block 708. For example, the access point may repeatedly(e.g., periodically) broadcast an APIDM message or some other suitablemessage (e.g., an existing message modified to include the pilotinformation or a new message including this information).

FIG. 8 describes sample operations that may be performed by an accessterminal in conjunction with generating a pilot report. As discussedherein, this pilot report is based, in part, on advertised pilotsignature-related information received from an access point.

As represented by block 802, the access terminal receives a pilot signalfrom an access point. As represented by block 804, the access terminalidentifies the pilot signature (e.g., PN offset or PN phase) that wasused by the access point to send the pilot signal (e.g., using knowntechniques).

As represented by block 806, the access terminal also receives a message(e.g., APIDM) from the access point. As discussed herein, this messageincludes at least one pilot signature indicator allocated for thataccess point and, optionally, defined pilot signal strength informationfor each pilot signature indicator.

As represented by block 808, the access terminal optionally determinespilot phase values (e.g., PN phases) associated with the at least onepilot signature indicator received at block 806 and, if necessary, thepilot signature determined at block 804. For example, in the event areceived pilot signature indicator comprises a set of PN offsets, theaccess terminal may use the following formula to calculate the PN phase(designated PN_Phase_(i)) for each PN offset (designated PN_(i)):PN_Phase_(i)=(PILOT_ARRIVAL+(64×PN_(i))) mod 2¹⁵. Here, PILOT_ARRIVAL isthe measured arrival time of the physical femto access point pilot(e.g., as defined in section 2.6.6.2.4 of C.S0005-E).

As represented by block 810, the access terminal generates a pilotreport that includes at least one indication based on the pilotsignature indicator(s) received at block 806 and an indication based onthe pilot signature identified at block 804. For example, theseindications may correspond directly to the received indicator(s) andidentified pilot signature or these indications may correspond to thepilot phase values (e.g., PN phases) determined at block 808.

The pilot report also includes a pilot signal strength indication foreach indication entry in the report. For example, the access terminalmay measure the signal strength of the pilot signal received at block802 and include an indication of this value in the pilot report. In somecases, the pilot signal strength indication for each advertised pilotsignature indicator also may be set to this same value. Alternatively,the access terminal may include any pilot signal strength informationreceived at block 806 in the pilot report entry for each advertisedpilot signature indicator.

As represented by block 812, the access terminal transmits the pilotreport (e.g., a PSMM or Route Update) generated at block 810. Forexample, the access terminal may send the report to a serving macroaccess point (e.g., a macro base station or access network) for furtherprocessing.

FIG. 9 describes sample operations that may be performed in conjunctionwith identifying a handover target based on access point pilot signatureinformation as taught herein. Two versions of these operations aredescribed. One version (e.g., corresponding to the system 500 of FIG. 5)uses pilot signature indicators such as PN phase indicators to identifya target and the other version (e.g., corresponding to the system 400 ofFIG. 4) uses cell identifiers to identity a target. These operations maybe performed, for example, by a network entity such as a femtoconvergence server, a femto gateway, or an access network.

As represented by block 902, at some point in time, a pilot signatureindicator mapping or a cell identifier mapping is determined for a setof access points. Here, a pilot signature indicator mapping mapsdifferent access points with different sets of pilot signatureindicators. For example, a given access point may be mapped to the twoPN phases (corresponding to two PN offsets) that were allocated for thataccess point by the femto convergence server. Similarly, a cellidentifier mapping maps different access points with different set ofcells identifiers. For example, a given access point may be mapped totwo cell identifiers (corresponding to two PN offsets) allocated forthat access point by the femto convergence server.

An entity may determine this mapping in various ways. In someimplementations, a network entity (e.g., a femto convergence server or afemto gateway) generates the mapping (e.g., based on configurationinformation received from the femto management system). In someimplementations the network entity receives the mapping from anothernetwork entity (e.g., from the femto management system).

As represented by block 904, at some point in time, the network entityreceives a message for handover of an access terminal. As discussedherein, this message may include, for example, pilot signatureindicators (e.g., for system 500) or cell identifiers (e.g., for system400). In addition, this message may include received pilot signalstrength indications as discussed herein.

As represented by block 906, the network entity may determine whethermore than one pilot signature indictor or cell identifier is needed foridentifying a target access point. For example, in accordance withconventional practice, a PN phase or cell identifier identified in thehandover message (i.e., from the pilot report) may be uniquelyassociated with a single access point (e.g., a non-femto cell). In theevent this PN phase or cell identifier is associated with the strongestreceived pilot strength, the target may be identified based solely onthe corresponding pilot signature indicator or cell identifier.

For other access points (e.g. femto cells), however, uniqueidentification of the access point is achieved only through the use ofmultiple pilot signature indicators or cell identifiers. In accordancewith the teachings herein, the network entity may determine whethermultiple pilot signature indicators or cell identifiers need to be usedto identify a target based on analysis of the pilot signature indicatorsreceived in the message. For example, as discussed above, a dedicatedset of PN offsets may be allocated for being advertised only (i.e., notused for sending an actual pilot signal). Thus, the value (e.g., PNphase 2-15) of a pilot signature indicator or cell identifier (e.g.,cell ID 2-15) may indicate that it is associated with a specific type ofaccess point (e.g., femto cell) and that this pilot signature indicatoror cell identifier is to be used in conjunction with at least one otherpilot signature indicator or cell identifier to uniquely identify anaccess point.

As represented by block 908, the target access point for handover of theaccess terminal is identified based on the mapping and the receivedpilot signature-related information. For example, the network entity maycompare the received PN phase indicators (or cell identifiers) with theentries in the mapping to identify the access point that transmitted thepilot signal and the message that caused these PN phases indicators (orcell identifiers) to be sent to the target network entity. As a specificexample, if the highest received signal strength in the measurementreport is associated with PN phases 0 and 2, the network entitydetermines which entry in the mapping contains this set of PN phases.The network entity may then look up the identity of the correspondingaccess point from this entry.

Also, in some cases, the identification of the target access point isbased on the received pilot signal strength indications. For example, ina situation where multiple access points are identified by the receivedpilot signature-related information, the access point associated withthe highest pilot signal strength indication (e.g., for the actual pilotsignal) may be selected.

In addition, in some implementations, the pilot signal strengthindications are used to form the identity signature for an access point.In this case, the mapping determined at block 902 will include the pilotsignal strength information that was designated for the access points.The network entity may thus identify a target access point by comparingthe pilot signal strength indications received at block 904 with thepilot signal strength indicator entries in the mapping. For example, twodifferent access points may be allocated the same PN offsets, butdifferent pilot signal strength indications. Thus, the identification ofan access point may be based on both the PN offsets and the pilot signalstrength indications.

As represented by block 910, once the appropriate target has beenidentified, the network entity may facilitate handover of the accessterminal to the target (e.g., by informing the source access point ofthe identity of the target access point).

For purposes of illustration, FIGS. 10 and 11 illustrate how messagingas taught herein may be implemented in different types of networkarchitectures. FIG. 10 depicts a simplified example of a CDMA 1x femtosystem 1000 (e.g., corresponding to the system 400 of FIG. 4). FIG. 11depicts a simplified example of a CDMA HRPD femto system 1100 (e.g.,corresponding to the system 500 of FIG. 5).

Referring initially to FIG. 10, a femto access point (FAP) communicateswith a core network via a femto gateway (FGW). An IPsec tunnel isestablished between the femto access point and the femto gateway forcarrying, for example, user traffic, Internet Protocol (IP) traffic, andcontrol traffic. For example, the media gateway control function/mediagateway (MGCF/MGW) facilitates the transfer of user traffic from thecore network to the femto access point via an Fx1 interface. Similarly,an Fx2 interface is used to transfer IMS traffic to and from the femtoaccess point. A femto management system (FMS) sends configuration andother information to the femto access point via an Fm interface and toother network entities such as a femto convergence server (connectionnot shown).

An example of handover operations performed by the system 1000 inaccordance with the teachings herein follows. A mobile station (MS)receives an APIDM including at least one PN offset from the femto accesspoint (FAP) and sends a PSMM including the corresponding PN phaseinformation to a macro base station (BS). The macro BS converts thepilot PN phase information to cell identifiers and sends the resultingpilot signature information to the MSC/MSCe via the A1/A1p interface.Here, a femto convergence server (FCS) appears as a target mobileswitching center (MSC) to the macro 1x infrastructure system. Thus, theFCS identifies the target 1x femto access point based on information theFCS receives via an IS-41 FACDIR2 message from the MSC/MSCe.

Referring to FIG. 11, a femto access point (FAP) communicates with thenetwork via a security gateway (SeGW) and a femto gateway (FGW). AnIPsec tunnel is established between the femto access point and thesecurity gateway for carrying, for example, user traffic, InternetProtocol (IP) traffic, and control traffic. For example, traffic betweenthe femto access point and a macro HRPD access network/packet controlfunction (AN/PCF) is carried over the A13, A16 and A24 interfaces.Traffic between the femto access point and an accessnetwork-authentication, authorization and accounting entity (AN-AAA) iscarried over an A12 interface. Traffic between the femto access pointand a packet data serving node (PDSN) is carried over the A10 and A11interfaces. A femto management system (FMS) sends configuration andother information to the femto access point via an Fm interface and toother network entities such as the femto gateway (connection not shown).

An example of handover operations performed by the system 1100 inaccordance with the teachings herein follows. An access terminal (AT)receives an APIDM including at least one PN offset from the femto accesspoint (FAP) and sends a PSMM including the corresponding PN phaseinformation to a macro access network (AN) entity. The macro accessnetwork sends the PN phase information to the femto gateway via anembedded Route Update message sent over the A16 interface. Here, thefemto gateway performs an A16 proxy function to allow the macro accessnetwork to handoff to the femto system without requiring any changes tothe macro access network. The femto gateway identifies the target femtoaccess point based on the information in the Route Update message.

Various fields that may be provided in a message such an APIDM tosupport pilot signature indicators as taught herein. Two examplesfollow.

In a first example, a first field (e.g., 1 bit) corresponding to avariable HO_PN_GROUP_INCL is set to a 1 when a PN offset group isadvertised in the message. Otherwise the first field is set to a 0. Asecond field (e.g., 0 or 4 bits) corresponding to a variableHO_PN_GROUP_COUNT contains the number of PN offsets following thisfield. A third field (e.g., 0 or (9xLOC_REC_LEN) bits) corresponding toa variable PN_OFFSET_GROUP contains an array of 9-bit fields, eachlisting PN offsets. Here, LOC_REC_LEN may correspond to maximum numberof available PN offsets. Also, the numbering (or offsetting) of these PNoffsets may need to be compatible with the PN_Inc (indicative of thephase spacing being employed) of the macro base stations.

In a second example (see Table 3.7.2.3.2.39-5 in C.S0005-E v2.0), anAPIDM includes a first field (e.g., 3 bits) corresponding to a variableHO_INFO_TYPE that is set to different values to indicate the type ofinformation that is included in a third field. For example, a value of“001” in the first field indicates that the third field includes asignature for a PSMM. Conversely, a value of “010” in the first fieldindicates that the third field includes a signature for a Route Updatemessage. A second field (e.g., 8 bits) corresponding to a variableHO_INFO_LEN is set to the length of the third field. The third field(e.g., HO_INFO_LEN bits) includes information that depends on the valueof the first field as described above.

For a HO_INFO_TYPE of “001”, the third field includes a PSMM_SIG_COUNTfield (e.g., 3 bits) and a PSMM_SIGNATURE field (e.g., 21 bits). ThePSMM_SIG_COUNT field is set to the number of occurrences of thePSMM_SIGNATURE field. The PSMM_SIGNATURE field is set to the signatureof the base station to be included in PSMM during handoff. The 15 MSBsare used in PILOT_PN_PHASE field and the 6 LSBs are used in PILOTSTRENGTH field.

For a HO_INFO_TYPE of “010”, the third field includes a RUP_SIG_COUNTfield (e.g., 3 bits) and a RUP_SIGNATURE field (e.g., 21 bits). TheRUP_SIG_COUNT field is set to the number of occurrences of theRUP_SIGNATURE field. The RUP_SIGNATURE field is set to the signature tobe included in a Route Update message during handoff from another HRPDaccess network to the HRPD access network associated with the basestation. The 15 MSBs are used in PilotPNPhase field and the 6 LSBs areused in PilotStrength field.

Various advantages may be achieved in a system implemented in accordancewith the teachings herein. Significantly, the macro infrastructure neednot be upgraded to support handover (e.g., active handover to femtocells) as taught herein. Rather, existing database structures (e.g., PNphase and cell identifier lists) only need to be configured to includethe additional allocated PN phases, cell identifiers, etc. Moreover, dueto the large number of unique signatures that may be created (e.g., byallocating 2, 3, 4, or more PN offsets for an access point), accuratehandover may always be achieved for any currently practical system.Also, the described techniques are scalable since, for example, the sizeof the allocated PN offset groups may be expanded as needed. Also, thedescribed techniques involve relatively simple algorithms in the femtoconvergence server and the femto gateway.

FIG. 12 illustrates several sample components that may be incorporatedinto nodes such as an access terminal 1202, an access point 1204 (e.g.,a femto cell), a network entity 1206 (e.g., a FCS or a FGW), and anetwork entity 1208 (e.g., an FMS) to perform access pointidentification operations as taught herein. In practice, the describedcomponents also may be incorporated into other nodes in a communicationsystem. For example, other nodes in a system may include componentssimilar to those described for the network entity 1208 to providesimilar allocation functionality. Also, a given node may contain one ormore of the described components. For example, an access point maycontain multiple transceiver components that enable the access point tooperate on multiple frequencies and/or communicate via differenttechnologies.

As shown in FIG. 12, the access terminal 1202 and the access point 1204include transceivers 1210 and 1212, respectively, for communicating withother nodes. The transceiver 1210 includes a transmitter 1214 forsending signals (e.g., messages and reports) and a receiver 1216 forreceiving signals (e.g., pilot signals and messages). Similarly, thetransceiver 1212 includes a transmitter 1218 for sending signals (e.g.,pilot signals and messages) and a receiver 1220 for receiving signals(e.g., messages, indicators, and indications).

The access point 1204, the network entity 1206, and the network entity1208 include network interfaces 1222, 1224, and 1226, respectively, forcommunicating with other nodes (e.g., other network nodes). For example,the network interfaces 1222, 1224, and 1226 may be configured tocommunicate with one or more network nodes via a wire-based or wirelessbackhaul. In some aspects, each network interface may be implemented asa transceiver configured to support wire-based or wirelesscommunication. For example, the network interface 1224 is depicted asincluding a transmitter component 1228 (e.g., for sending messages) anda receiver component 1230 (e.g., for receiving messages), while thenetwork interface 1226 is depicted as including a transmitter component1232 (e.g., for sending messages) and a receiver component 1234 (e.g.,for receiving messages).

The access terminal 1202, the access point 1204, the network entity1206, and the network entity 1208 also include other components that maybe used in conjunction with access point identification operations astaught herein. For example, the access terminal 1202 includes a pilotprocessor 1236 for performing pilot signature-related operations (e.g.,generating a pilot report, determining pilot phase values, identifyingpilot signatures) and for providing other related functionality astaught herein. The access point 1204 includes a pilot processor 1238 forperforming pilot signature-related operations (e.g., generating messagesincluding pilot signature-related indications, defining pilot signalstrength indications) and for providing other related functionality astaught herein. The network entity 1208 includes a pilot processor 1240for performing pilot signature-related operations (e.g., allocatingpilot signature indicators, defining pilot signal strength indications,determining that more than one pilot signature indicator is to beallocated, identifying unallocated pilot signatures) and for providingother related functionality as taught herein. The network entity 1206includes a handover controller 1242 for performing handover-relatedoperations (e.g., determining a cell identifier mapping, determining apilot signature indicator mapping, identifying a handover target,determining that a target is to be identified from a plurality of cellidentifiers) and for providing other related functionality as taughtherein.

In some implementations, the components of FIG. 12 may be implemented inone or more processors (e.g., that uses and/or incorporates data memoryfor storing information or code used by the processor(s) to provide thisfunctionality). For example, the functionality of pilot processor 1236(and optionally some of the functionality of transceiver 1210) may beimplemented by a processor or processors of an access terminal and datamemory of the access terminal (e.g., by execution of appropriate codeand/or by appropriate configuration of processor components). Similarly,the functionality of pilot processor 1238 (and optionally some of thefunctionality of transceiver 1212 and/or network interface 1222) may beimplemented by a processor or processors of an access point and datamemory of the access point (e.g., by execution of appropriate codeand/or by appropriate configuration of processor components). Thefunctionality of handover controller 1242 (and optionally some of thefunctionality of network interface 1224) may be implemented by aprocessor or processors of a network entity and data memory of thenetwork entity (e.g., by execution of appropriate code and/or byappropriate configuration of processor components). The functionality ofpilot processor 1240 (and optionally some of the functionality ofnetwork interface 1226) may be implemented by a processor or processorsof a network entity and data memory of the network entity (e.g., byexecution of appropriate code and/or by appropriate configuration ofprocessor components).

As discussed above, in some aspects the teachings herein may be employedin a network that includes macro scale coverage (e.g., a large areacellular network such as a 3G network, typically referred to as a macrocell network or a WAN) and smaller scale coverage (e.g., aresidence-based or building-based network environment, typicallyreferred to as a LAN). As an access terminal (AT) moves through such anetwork, the access terminal may be served in certain locations byaccess points that provide macro coverage while the access terminal maybe served at other locations by access points that provide smaller scalecoverage. In some aspects, the smaller coverage nodes may be used toprovide incremental capacity growth, in-building coverage, and differentservices (e.g., for a more robust user experience).

In the description herein, a node (e.g., an access point) that providescoverage over a relatively large area may be referred to as a macroaccess point while a node that provides coverage over a relatively smallarea (e.g., a residence) may be referred to as a femto access point. Itshould be appreciated that the teachings herein may be applicable tonodes associated with other types of coverage areas. For example, a picoaccess point may provide coverage (e.g., coverage within a commercialbuilding) over an area that is smaller than a macro area and larger thana femto area. In various applications, other terminology may be used toreference a macro access point, a femto access point, or other accesspoint-type nodes. For example, a macro access point may be configured orreferred to as an access network, base station, access point, eNodeB,macro cell, and so on. Also, a femto access point may be configured orreferred to as a Home NodeB, Home eNodeB, access point base station,femto cell, and so on. In some implementations, a node may be associatedwith (e.g., referred to as or divided into) one or more cells orsectors. A cell or sector associated with a macro access point, a femtoaccess point, or a pico access point may be referred to as a macro cell,a femto cell, or a pico cell, respectively.

FIG. 13 illustrates a wireless communication system 1300, configured tosupport a number of users, in which the teachings herein may beimplemented. The system 1300 provides communication for multiple cells1302, such as, for example, macro cells 1302A-1302G, with each cellbeing serviced by a corresponding access point 1304 (e.g., access points1304A-1304G). As shown in FIG. 13, access terminals 1306 (e.g., accessterminals 1306A-1306L) may be dispersed at various locations throughoutthe system over time. Each access terminal 1306 may communicate with oneor more access points 1304 on a forward link (FL) and/or a reverse link(RL) at a given moment, depending upon whether the access terminal 1306is active and whether it is in soft handoff, for example. The wirelesscommunication system 1300 may provide service over a large geographicregion. For example, macro cells 1302A-1302G may cover a few blocks in aneighborhood or several miles in rural environment.

FIG. 14 illustrates an exemplary communication system 1400 where one ormore femto access points are deployed within a network environment.Specifically, the system 1400 includes multiple femto access points 1410(e.g., femto access points 1410A and 1410B) installed in a relativelysmall scale network environment (e.g., in one or more user residences1430). Each femto access point 1410 may be coupled to a wide areanetwork 1440 (e.g., the Internet) and a mobile operator core network1450 via a DSL router, a cable modem, a wireless link, or otherconnectivity means (not shown). As will be discussed below, each femtoaccess point 1410 may be configured to serve associated access terminals1420 (e.g., access terminal 1420A) and, optionally, other (e.g., hybridor alien) access terminals 1420 (e.g., access terminal 1420B). In otherwords, access to femto access points 1410 may be restricted whereby agiven access terminal 1420 may be served by a set of designated (e.g.,home) femto access point(s) 1410 but may not be served by anynon-designated femto access points 1410 (e.g., a neighbor's femto accesspoint 1410).

FIG. 15 illustrates an example of a coverage map 1500 where severaltracking areas 1502 (or routing areas or location areas) are defined,each of which includes several macro coverage areas 1504. Here, areas ofcoverage associated with tracking areas 1502A, 1502B, and 1502C aredelineated by the wide lines and the macro coverage areas 1504 arerepresented by the larger hexagons. The tracking areas 1502 also includefemto coverage areas 1506. In this example, each of the femto coverageareas 1506 (e.g., femto coverage areas 1506B and 1506C) is depictedwithin one or more macro coverage areas 1504 (e.g., macro coverage areas1504A and 1504B). It should be appreciated, however, that some or all ofa femto coverage area 1506 may not lie within a macro coverage area1504. In practice, a large number of femto coverage areas 1506 (e.g.,femto coverage areas 1506A and 1506D) may be defined within a giventracking area 1502 or macro coverage area 1504. Also, one or more picocoverage areas (not shown) may be defined within a given tracking area1502 or macro coverage area 1504.

Referring again to FIG. 14, the owner of a femto access point 1410 maysubscribe to mobile service, such as, for example, 3G mobile service,offered through the mobile operator core network 1450. In addition, anaccess terminal 1420 may be capable of operating both in macroenvironments and in smaller scale (e.g., residential) networkenvironments. In other words, depending on the current location of theaccess terminal 1420, the access terminal 1420 may be served by a macrocell access point 1460 associated with the mobile operator core network1450 or by any one of a set of femto access points 1410 (e.g., the femtoaccess points 1410A and 1410B that reside within a corresponding userresidence 1430). For example, when a subscriber is outside his home, heis served by a standard macro access point (e.g., access point 1460) andwhen the subscriber is at home, he is served by a femto access point(e.g., access point 1410A). Here, a femto access point 1410 may bebackward compatible with legacy access terminals 1420.

A femto access point 1410 may be deployed on a single frequency or, inthe alternative, on multiple frequencies. Depending on the particularconfiguration, the single frequency or one or more of the multiplefrequencies may overlap with one or more frequencies used by a macroaccess point (e.g., access point 1460).

In some aspects, an access terminal 1420 may be configured to connect toa preferred femto access point (e.g., the home femto access point of theaccess terminal 1420) whenever such connectivity is possible. Forexample, whenever the access terminal 1420A is within the user'sresidence 1430, it may be desired that the access terminal 1420Acommunicate only with the home femto access point 1410A or 1410B.

In some aspects, if the access terminal 1420 operates within the macrocellular network 1450 but is not residing on its most preferred network(e.g., as defined in a preferred roaming list), the access terminal 1420may continue to search for the most preferred network (e.g., thepreferred femto access point 1410) using a better system reselection(BSR) procedure, which may involve a periodic scanning of availablesystems to determine whether better systems are currently available andsubsequently acquire such preferred systems. The access terminal 1420may limit the search for specific band and channel. For example, one ormore femto channels may be defined whereby all femto access points (orall restricted femto access points) in a region operate on the femtochannel(s). The search for the most preferred system may be repeatedperiodically. Upon discovery of a preferred femto access point 1410, theaccess terminal 1420 selects the femto access point 1410 and registerson it for use when within its coverage area.

Access to a femto access point may be restricted in some aspects. Forexample, a given femto access point may only provide certain services tocertain access terminals. In deployments with so-called restricted (orclosed) access, a given access terminal may only be served by the macrocell mobile network and a defined set of femto access points (e.g., thefemto access points 1410 that reside within the corresponding userresidence 1430). In some implementations, an access point may berestricted to not provide, for at least one node (e.g., accessterminal), at least one of: signaling, data access, registration,paging, or service.

In some aspects, a restricted femto access point (which may also bereferred to as a Closed Subscriber Group Home NodeB) is one thatprovides service to a restricted provisioned set of access terminals.This set may be temporarily or permanently extended as necessary. Insome aspects, a Closed Subscriber Group (CSG) may be defined as the setof access points (e.g., femto access points) that share a common accesscontrol list of access terminals.

Various relationships may thus exist between a given femto access pointand a given access terminal. For example, from the perspective of anaccess terminal, an open femto access point may refer to a femto accesspoint with unrestricted access (e.g., the femto access point allowsaccess to any access terminal). A restricted femto access point mayrefer to a femto access point that is restricted in some manner (e.g.,restricted for access and/or registration). A home femto access pointmay refer to a femto access point on which the access terminal isauthorized to access and operate on (e.g., permanent access is providedfor a defined set of one or more access terminals). A hybrid (or guest)femto access point may refer to a femto access point on which differentaccess terminals are provided different levels of service (e.g., someaccess terminals may be allowed partial and/or temporary access whileother access terminals may be allowed full access). An alien femtoaccess point may refer to a femto access point on which the accessterminal is not authorized to access or operate on, except for perhapsemergency situations (e.g., 911 calls).

From a restricted femto access point perspective, a home access terminalmay refer to an access terminal that is authorized to access therestricted femto access point installed in the residence of that accessterminal's owner (usually the home access terminal has permanent accessto that femto access point). A guest access terminal may refer to anaccess terminal with temporary access to the restricted femto accesspoint (e.g., limited based on deadline, time of use, bytes, connectioncount, or some other criterion or criteria). An alien access terminalmay refer to an access terminal that does not have permission to accessthe restricted femto access point, except for perhaps emergencysituations, for example, such as 911 calls (e.g., an access terminalthat does not have the credentials or permission to register with therestricted femto access point).

For convenience, the disclosure herein describes various functionalityin the context of a femto access point. It should be appreciated,however, that a pico access point may provide the same or similarfunctionality for a larger coverage area. For example, a pico accesspoint may be restricted, a home pico access point may be defined for agiven access terminal, and so on.

The teachings herein may be employed in a wireless multiple-accesscommunication system that simultaneously supports communication formultiple wireless access terminals. Here, each terminal may communicatewith one or more access points via transmissions on the forward andreverse links. The forward link (or downlink) refers to thecommunication link from the access points to the terminals, and thereverse link (or uplink) refers to the communication link from theterminals to the access points. This communication link may beestablished via a single-in-single-out system, amultiple-in-multiple-out (MIMO) system, or some other type of system.

A MIMO system employs multiple (N_(T)) transmit antennas and multiple(N_(R)) receive antennas for data transmission. A MIMO channel formed bythe N_(T) transmit and N_(R) receive antennas may be decomposed intoN_(S) independent channels, which are also referred to as spatialchannels, where N_(S)≦min{N_(T), N_(R)}. Each of the N_(S) independentchannels corresponds to a dimension. The MIMO system may provideimproved performance (e.g., higher throughput and/or greaterreliability) if the additional dimensionalities created by the multipletransmit and receive antennas are utilized.

A MIMO system may support time division duplex (TDD) and frequencydivision duplex (FDD). In a TDD system, the forward and reverse linktransmissions are on the same frequency region so that the reciprocityprinciple allows the estimation of the forward link channel from thereverse link channel. This enables the access point to extract transmitbeam-forming gain on the forward link when multiple antennas areavailable at the access point.

FIG. 16 illustrates a wireless device 1610 (e.g., an access point) and awireless device 1650 (e.g., an access terminal) of a sample MIMO system1600. At the device 1610, traffic data for a number of data streams isprovided from a data source 1612 to a transmit (TX) data processor 1614.Each data stream may then be transmitted over a respective transmitantenna.

The TX data processor 1614 formats, codes, and interleaves the trafficdata for each data stream based on a particular coding scheme selectedfor that data stream to provide coded data. The coded data for each datastream may be multiplexed with pilot data using OFDM techniques. Thepilot data is typically a known data pattern that is processed in aknown manner and may be used at the receiver system to estimate thechannel response. The multiplexed pilot and coded data for each datastream is then modulated (i.e., symbol mapped) based on a particularmodulation scheme (e.g., BPSK, QSPK, M-PSK, or M-QAM) selected for thatdata stream to provide modulation symbols. The data rate, coding, andmodulation for each data stream may be determined by instructionsperformed by a processor 1630. A data memory 1632 may store programcode, data, and other information used by the processor 1630 or othercomponents of the device 1610.

The modulation symbols for all data streams are then provided to a TXMIMO processor 1620, which may further process the modulation symbols(e.g., for OFDM). The TX MIMO processor 1620 then provides N_(T)modulation symbol streams to N_(T) transceivers (XCVR) 1622A through1622T. In some aspects, the TX MIMO processor 1620 applies beam-formingweights to the symbols of the data streams and to the antenna from whichthe symbol is being transmitted.

Each transceiver 1622 receives and processes a respective symbol streamto provide one or more analog signals, and further conditions (e.g.,amplifies, filters, and upconverts) the analog signals to provide amodulated signal suitable for transmission over the MIMO channel. N_(T)modulated signals from transceivers 1622A through 1622T are thentransmitted from N_(T) antennas 1624A through 1624T, respectively.

At the device 1650, the transmitted modulated signals are received byN_(R) antennas 1652A through 1652R and the received signal from eachantenna 1652 is provided to a respective transceiver (XCVR) 1654Athrough 1654R. Each transceiver 1654 conditions (e.g., filters,amplifies, and downconverts) a respective received signal, digitizes theconditioned signal to provide samples, and further processes the samplesto provide a corresponding “received” symbol stream.

A receive (RX) data processor 1660 then receives and processes the N_(R)received symbol streams from N_(R) transceivers 1654 based on aparticular receiver processing technique to provide N_(T) “detected”symbol streams. The RX data processor 1660 then demodulates,deinterleaves, and decodes each detected symbol stream to recover thetraffic data for the data stream. The processing by the RX dataprocessor 1660 is complementary to that performed by the TX MIMOprocessor 1620 and the TX data processor 1614 at the device 1610.

A processor 1670 periodically determines which pre-coding matrix to use(discussed below). The processor 1670 formulates a reverse link messagecomprising a matrix index portion and a rank value portion. A datamemory 1672 may store program code, data, and other information used bythe processor 1670 or other components of the device 1650.

The reverse link message may comprise various types of informationregarding the communication link and/or the received data stream. Thereverse link message is then processed by a TX data processor 1638,which also receives traffic data for a number of data streams from adata source 1636, modulated by a modulator 1680, conditioned by thetransceivers 1654A through 1654R, and transmitted back to the device1610.

At the device 1610, the modulated signals from the device 1650 arereceived by the antennas 1624, conditioned by the transceivers 1622,demodulated by a demodulator (DEMOD) 1640, and processed by a RX dataprocessor 1642 to extract the reverse link message transmitted by thedevice 1650. The processor 1630 then determines which pre-coding matrixto use for determining the beam-forming weights then processes theextracted message.

FIG. 16 also illustrates that the communication components may includeone or more components that perform pilot control operations as taughtherein. For example, a pilot control component 1690 may cooperate withthe processor 1630 and/or other components of the device 1610 to receivepilot-related signals from another device (e.g., device 1650) andtransmit pilot reports as taught herein. Similarly, a pilot controlcomponent 1692 may cooperate with the processor 1670 and/or othercomponents of the device 1650 to send pilot signals to another device(e.g., device 1610) and receive configuration information from anotherdevice as taught herein. It should be appreciated that for each device1610 and 1650 the functionality of two or more of the describedcomponents may be provided by a single component. For example, a singleprocessing component may provide the functionality of the pilot controlcomponent 1690 and the processor 1630 and a single processing componentmay provide the functionality of the pilot control component 1692 andthe processor 1670.

The teachings herein may be incorporated into various types ofcommunication systems and/or system components. In some aspects, theteachings herein may be employed in a multiple-access system capable ofsupporting communication with multiple users by sharing the availablesystem resources (e.g., by specifying one or more of bandwidth, transmitpower, coding, interleaving, and so on). For example, the teachingsherein may be applied to any one or combinations of the followingtechnologies: Code Division Multiple Access (CDMA) systems,Multiple-Carrier CDMA (MCCDMA), Wideband CDMA (W-CDMA), High-SpeedPacket Access (HSPA, HSPA+) systems, Time Division Multiple Access(TDMA) systems, Frequency Division Multiple Access (FDMA) systems,Single-Carrier FDMA (SC-FDMA) systems, Orthogonal Frequency DivisionMultiple Access (OFDMA) systems, or other multiple access techniques. Awireless communication system employing the teachings herein may bedesigned to implement one or more standards, such as IS-95, cdma2000,IS-856, W-CDMA, TDSCDMA, and other standards. A CDMA network mayimplement a radio technology such as Universal Terrestrial Radio Access(UTRA), cdma2000, or some other technology. UTRA includes W-CDMA and LowChip Rate (LCR). The cdma2000 technology covers IS-2000, IS-95 andIS-856 standards. A TDMA network may implement a radio technology suchas Global System for Mobile Communications (GSM). An OFDMA network mayimplement a radio technology such as Evolved UTRA (E-UTRA), IEEE 802.11,IEEE 802.16, IEEE 802.20, Flash-OFDM®, etc. UTRA, E-UTRA, and GSM arepart of Universal Mobile Telecommunication System (UMTS). The teachingsherein may be implemented in a 3GPP Long Term Evolution (LTE) system, anUltra-Mobile Broadband (UMB) system, and other types of systems. LTE isa release of UMTS that uses E-UTRA. UTRA, E-UTRA, GSM, UMTS and LTE aredescribed in documents from an organization named “3rd GenerationPartnership Project” (3GPP), while cdma2000 is described in documentsfrom an organization named “3rd Generation Partnership Project 2”(3GPP2). Although certain aspects of the disclosure may be describedusing 3GPP terminology, it is to be understood that the teachings hereinmay be applied to 3GPP (e.g., Re199, Re15, Re16, Re17) technology, aswell as 3GPP2 (e.g., 1xRTT, 1xEV-DO Rel0, RevA, RevB) technology andother technologies.

The teachings herein may be incorporated into (e.g., implemented withinor performed by) a variety of apparatuses (e.g., nodes). In someaspects, a node (e.g., a wireless node) implemented in accordance withthe teachings herein may comprise an access point or an access terminal

For example, an access terminal may comprise, be implemented as, orknown as user equipment, a subscriber station, a subscriber unit, amobile station, a mobile, a mobile node, a remote station, a remoteterminal, a user terminal, a user agent, a user device, or some otherterminology. In some implementations an access terminal may comprise acellular telephone, a cordless telephone, a session initiation protocol(SIP) phone, a wireless local loop (WLL) station, a personal digitalassistant (PDA), a handheld device having wireless connectioncapability, or some other suitable processing device connected to awireless modem. Accordingly, one or more aspects taught herein may beincorporated into a phone (e.g., a cellular phone or smart phone), acomputer (e.g., a laptop), a portable communication device, a portablecomputing device (e.g., a personal data assistant), an entertainmentdevice (e.g., a music device, a video device, or a satellite radio), aglobal positioning system device, or any other suitable device that isconfigured to communicate via a wireless medium.

An access point may comprise, be implemented as, or known as a NodeB, aneNodeB, a radio network controller (RNC), a base station (BS), a radiobase station (RBS), a base station controller (BSC), a base transceiverstation (BTS), a transceiver function (TF), a radio transceiver, a radiorouter, a basic service set (BSS), an extended service set (ESS), amacro cell, a macro node, a Home eNB (HeNB), a femto cell, a femto node,a pico node, or some other similar terminology.

In some aspects a node (e.g., an access point) may comprise an accessnode for a communication system. Such an access node may provide, forexample, connectivity for or to a network (e.g., a wide area networksuch as the Internet or a cellular network) via a wired or wirelesscommunication link to the network. Accordingly, an access node mayenable another node (e.g., an access terminal) to access a network orsome other functionality. In addition, it should be appreciated that oneor both of the nodes may be portable or, in some cases, relativelynon-portable.

Also, it should be appreciated that a wireless node may be capable oftransmitting and/or receiving information in a non-wireless manner(e.g., via a wired connection). Thus, a receiver and a transmitter asdiscussed herein may include appropriate communication interfacecomponents (e.g., electrical or optical interface components) tocommunicate via a non-wireless medium.

A wireless node may communicate via one or more wireless communicationlinks that are based on or otherwise support any suitable wirelesscommunication technology. For example, in some aspects a wireless nodemay associate with a network. In some aspects the network may comprise alocal area network or a wide area network. A wireless device may supportor otherwise use one or more of a variety of wireless communicationtechnologies, protocols, or standards such as those discussed herein(e.g., CDMA, TDMA, OFDM, OFDMA, WiMAX, Wi-Fi, and so on). Similarly, awireless node may support or otherwise use one or more of a variety ofcorresponding modulation or multiplexing schemes. A wireless node maythus include appropriate components (e.g., air interfaces) to establishand communicate via one or more wireless communication links using theabove or other wireless communication technologies. For example, awireless node may comprise a wireless transceiver with associatedtransmitter and receiver components that may include various components(e.g., signal generators and signal processors) that facilitatecommunication over a wireless medium.

The functionality described herein (e.g., with regard to one or more ofthe accompanying figures) may correspond in some aspects to similarlydesignated “means for” functionality in the appended claims. Referringto FIGS. 17-21, apparatuses 1700, 1800, 1900, 2000, and 2100 arerepresented as a series of interrelated functional modules. Here, amessage receiving module 1702 may correspond at least in some aspectsto, for example, a receiver as discussed herein. A pilot reportgenerating module 1704 may correspond at least in some aspects to, forexample, a pilot processor as discussed herein. A pilot reporttransmitting module 1706 may correspond at least in some aspects to, forexample, a transmitter as discussed herein. A pilot phase valuedetermining module 1708 may correspond at least in some aspects to, forexample, a pilot processor as discussed herein. A pilot signal receivingmodule 1710 may correspond at least in some aspects to, for example, areceiver as discussed herein. A pilot signature identifying module 1712may correspond at least in some aspects to, for example, a pilotprocessor as discussed herein. A pilot signature indicators receivingmodule 1802 may correspond at least in some aspects to, for example, areceiver as discussed herein. A pilot signal transmitting module 1804may correspond at least in some aspects to, for example, a transmitteras discussed herein. A message generating module 1806 may correspond atleast in some aspects to, for example, a pilot processor as discussedherein. A message transmitting module 1808 may correspond at least insome aspects to, for example, a transmitter as discussed herein. A pilotsignal strength indication defining module 1810 may correspond at leastin some aspects to, for example, a pilot processor as discussed herein.A pilot signal strength indication receiving module 1812 may correspondat least in some aspects to, for example, a receiver as discussedherein. A message receiving module 1902 may correspond at least in someaspects to, for example, a receiver as discussed herein. A cellidentifier mapping determining module 1904 may correspond at least insome aspects to, for example, a handover controller as discussed herein.A handover target identifying module 1906 may correspond at least insome aspects to, for example, a handover controller as discussed herein.A target identified from plurality of cell identifiers determiningmodule 1908 may correspond at least in some aspects to, for example, ahandover controller as discussed herein. A message receiving module 2002may correspond at least in some aspects to, for example, a receiver asdiscussed herein. A pilot signature indicator mapping determining module2004 may correspond at least in some aspects to, for example, a handovercontroller as discussed herein. A handover target identifying module2006 may correspond at least in some aspects to, for example, a handovercontroller as discussed herein. A target identified from plurality ofcell identifiers determining module 2008 may correspond at least in someaspects to, for example, a handover controller as discussed herein. Apilot signature indicators allocating module 2102 may correspond atleast in some aspects to, for example, a pilot processor as discussedherein. A message sending module 2104 may correspond at least in someaspects to, for example, a transmitter as discussed herein. A pilotsignal strength indication defining module 2106 may correspond at leastin some aspects to, for example, a pilot processor as discussed herein.A more than one pilot signature indicator determining module 2108 maycorrespond at least in some aspects to, for example, a pilot processoras discussed herein. An unallocated pilot signatures identifying module2110 may correspond at least in some aspects to, for example, a pilotprocessor as discussed herein.

The functionality of the modules of FIGS. 17-21 may be implemented invarious ways consistent with the teachings herein. In some aspects thefunctionality of these modules may be implemented as one or moreelectrical components. In some aspects the functionality of these blocksmay be implemented as a processing system including one or moreprocessor components. In some aspects the functionality of these modulesmay be implemented using, for example, at least a portion of one or moreintegrated circuits (e.g., an ASIC). As discussed herein, an integratedcircuit may include a processor, software, other related components, orsome combination thereof. The functionality of these modules also may beimplemented in some other manner as taught herein. In some aspects oneor more of any dashed blocks in FIGS. 17-21 are optional.

It should be understood that any reference to an element herein using adesignation such as “first,” “second,” and so forth does not generallylimit the quantity or order of those elements. Rather, thesedesignations may be used herein as a convenient method of distinguishingbetween two or more elements or instances of an element. Thus, areference to first and second elements does not mean that only twoelements may be employed there or that the first element must precedethe second element in some manner. Also, unless stated otherwise a setof elements may comprise one or more elements. In addition, terminologyof the form “at least one of: A, B, or C” used in the description or theclaims means “A or B or C or any combination of these elements.”

Those of skill in the art would understand that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or any combination thereof.

Those of skill would further appreciate that any of the variousillustrative logical blocks, modules, processors, means, circuits, andalgorithm steps described in connection with the aspects disclosedherein may be implemented as electronic hardware (e.g., a digitalimplementation, an analog implementation, or a combination of the two,which may be designed using source coding or some other technique),various forms of program or design code incorporating instructions(which may be referred to herein, for convenience, as “software” or a“software module”), or combinations of both. To clearly illustrate thisinterchangeability of hardware and software, various illustrativecomponents, blocks, modules, circuits, and steps have been describedabove generally in terms of their functionality. Whether suchfunctionality is implemented as hardware or software depends upon theparticular application and design constraints imposed on the overallsystem. Skilled artisans may implement the described functionality invarying ways for each particular application, but such implementationdecisions should not be interpreted as causing a departure from thescope of the present disclosure.

The various illustrative logical blocks, modules, and circuits describedin connection with the aspects disclosed herein may be implementedwithin or performed by an integrated circuit (IC), an access terminal,or an access point. The IC may comprise a general purpose processor, adigital signal processor (DSP), an application specific integratedcircuit (ASIC), a field programmable gate array (FPGA) or otherprogrammable logic device, discrete gate or transistor logic, discretehardware components, electrical components, optical components,mechanical components, or any combination thereof designed to performthe functions described herein, and may execute codes or instructionsthat reside within the IC, outside of the IC, or both. A general purposeprocessor may be a microprocessor, but in the alternative, the processormay be any conventional processor, controller, microcontroller, or statemachine. A processor may also be implemented as a combination ofcomputing devices, e.g., a combination of a DSP and a microprocessor, aplurality of microprocessors, one or more microprocessors in conjunctionwith a DSP core, or any other such configuration.

It is understood that any specific order or hierarchy of steps in anydisclosed process is an example of a sample approach. Based upon designpreferences, it is understood that the specific order or hierarchy ofsteps in the processes may be rearranged while remaining within thescope of the present disclosure. The accompanying method claims presentelements of the various steps in a sample order, and are not meant to belimited to the specific order or hierarchy presented.

In one or more exemplary embodiments, the functions described may beimplemented in hardware, software, firmware, or any combination thereof.If implemented in software, the functions may be stored on ortransmitted over as one or more instructions or code on acomputer-readable medium. Computer-readable media includes both computerstorage media and communication media including any medium thatfacilitates transfer of a computer program from one place to another. Astorage media may be any available media that can be accessed by acomputer. By way of example, and not limitation, such computer-readablemedia can comprise RAM, ROM, EEPROM, CD-ROM or other optical diskstorage, magnetic disk storage or other magnetic storage devices, or anyother medium that can be used to carry or store desired program code inthe form of instructions or data structures and that can be accessed bya computer. Also, any connection is properly termed a computer-readablemedium. For example, if the software is transmitted from a website,server, or other remote source using a coaxial cable, fiber optic cable,twisted pair, digital subscriber line (DSL), or wireless technologiessuch as infrared, radio, and microwave, then the coaxial cable, fiberoptic cable, twisted pair, DSL, or wireless technologies such asinfrared, radio, and microwave are included in the definition of medium.Disk and disc, as used herein, includes compact disc (CD), laser disc,optical disc, digital versatile disc (DVD), floppy disk and blu-ray discwhere disks usually reproduce data magnetically, while discs reproducedata optically with lasers. Combinations of the above should also beincluded within the scope of computer-readable media. It should beappreciated that a computer-readable medium may be implemented in anysuitable computer-program product.

The previous description of the disclosed aspects is provided to enableany person skilled in the art to make or use the present disclosure.Various modifications to these aspects will be readily apparent to thoseskilled in the art, and the generic principles defined herein may beapplied to other aspects without departing from the scope of thedisclosure. Thus, the present disclosure is not intended to be limitedto the aspects shown herein but is to be accorded the widest scopeconsistent with the principles and novel features disclosed herein.

What is claimed is:
 1. A method of communication, comprising: receivinga message from an access point at an access terminal, wherein themessage includes at least one pilot signature indicator associated withthe access point; generating a pilot report that includes at least oneindication based on the received at least one pilot signature indicator;and transmitting the pilot report.